Endocrine and Metabolism PDF

Metabolism & Endocrine Disorders Health Assessment Metabolism and Endocrine Goal of preoperative assessment is two fold: 1. Determine existence of disease if undiagnosed 2. Determine severity of disease/compliance with treatment if disease is present Inborn Errors of Metabolism Known as “nutritional...

Metabolism & Endocrine Disorders Health Assessment Metabolism and Endocrine Goal of preoperative assessment is two fold: 1. Determine existence of disease if undiagnosed 2. Determine severity of disease/compliance with treatment if disease is present Inborn Errors of Metabolism Known as “nutritional disturbances” Variety of clinical manifestations Often clinically asymptomatic until a trigger is given Porphyria Purine metabolism disorders Hyperlipidemia Carbohydrate metabolism disorders Amino acid metabolism disorders Mucopolysaccharidoses Porphyrias Deficiency of a specific enzyme in heme synthetic pathway Over production of porphyrins Essential for oxygen transport & storage Defect in enzymes of pathway cause accumulation of preceding form of porphyrin à porphyria Porphyria Classification Hepatic or erythropoietic Depends on primary site of overproduction or accumulation Only acute forms relate to anesthesia Hepatic à acute intermittent porphyria Acute Porphyria Attacks occur in females more than males 3rd and 4th decades of life Precipitated by events that decrease heme concentrations à increase production of porphrinogens Physiologic fluctuation in hormone levels in menstruation, fasting, dehydration, stress, infection History of spontaneous abortion Acute Porphyria Present with acute abdominal pain, autonomic nervous system instability, electrolyte disturbances, neuropsychiatric events Skeletal muscle weakness à respiratory failure CNS involvement à upper motor neurons, CN palsies, cerebellar and basal ganglia involvement Significant cardiovascular instability in face of hypovolemia Acute porphyria preoperative exam Tachycardia and hypertension Acute abdominal pain (autonomic neuropathy) Sodium, potassium, magnesium derangements History of triggering events (exposure to drugs) Drugs may be the #1 trigger by inducing activity of ALA synthetase Not always possible to predict Preoperative exam Careful family history if suspected No one laboratory test is predictive Presence or peripheral neuropathy Signs of autonomic disorders If suspect, delay and work up! Diabetes DM1 5-10%; DM2 90-95% DM1 à insulin deficiency T-cell mediated autoimmune destruction of beta cells Requires insulin DM2 à insulin resistance No known cause (obesity, hormonal imbalance) Symptoms/disease 4-7 years BEFORE diagnosis May or may not need insulin 25% of the US population has metabolic syndrome Insulin times Diabetes Evaluation Emphasis on CV, renal, neurologic, and MS systems Understand and know the specific regimen for DM management Dose, timing, and type of insulin used Focused history of DM control Focused physical exam with special attention to the airway, fat pads on neck and back, and ROM Prayer Sign Diabetes and CV High index of suspicion for MI Autonomic neuropathy leads to silent MI Early satiety, erectile dysfunction, neuropathy, post-prandial vomiting Absence of chest pain does not rule out MI Rule in/out autonomic neuropathy Orthostatic hypotension Resting tachycardia Spastic bladder Heartburn/vomiting after eating Appropriate CV testing Diabetes and Renal Renal function is impacted by DM Renal function testing including BUN/Cr, K, eGFR Volume status can be impacted History of ketoacidosis (DM1) or hyperglycemic hyperosmolar coma (DM2) Diabetes and Neurological PVD can lead to TIA/CVA History of TIA symptoms (silent) Presence and severity of peripheral neuropathy Discrepancy in BP reading across two sites Present and severity of autonomic neuropathy Orthostatic hypotension and resting tachycardia Gastroparesis due to autonomic neuropathy High aspiration risk Diabetic retinopathy Diabetes and MS Stiff joint syndrome Related to non-enzyme glycosylation of proteins & abnormal cross-linking of collagen NOT correlated to severity of DM Impaired joint mobility Cervical spine immobility à airway concerns History of difficult intubation Neck flexion/extension film Preoperative Insulin Normal doses until day of surgery Day of surgery 1/3 to 1/2 dose of LONG ACTING in the morning Immediate pre-operative BG level Continue insulin pumps at normal rate Monitor intraoperative BG levels Preoperative GLP-1 Agonists Guidelines are very new Recommendations include holding GLP-1 agonists at least 7 days prior to anesthetic if taking weekly (most) Hold day of surgery if taking daily (rare) Consider gastric ultrasound to determine gastric volume and contents Thyroid Disorders Hyperthyroidism Grave’s Disease Toxic multinodular goiter Toxic adenoma Hypermetabolic state Sweating, anxiety, catecholamine charged, diarrhea CV is most affected system Preoperative goal is determine efficacy of treatment Hyperthyroidism Elective surgery should be avoided in presence of acute thyroid storm Determine history of thyroid storm Other signs and symptoms of hypermetabolic state Best single blood test is TSH assay Determines thyroid hormone actions at cellular level Hypothoroidism Also called myxedema (very common disease) Slow, insidious onset of symptoms Gradual slowing of mental and physical activity CO decreased à decreased SV and HR ECG à flattened T waves, low amplitude P Reduced blood volume and increased SVR Preoperative focus on efficacy of treatment Pheochromocytoma Catecholamine-secreting tumor often found on adrenal gland (but not always) No known cause, 10% inherited Rare but life threatening under anesthesia Hypertension, reduced circulating volume, cardiomyopathy Exact symptoms depend on catecholamine secreted Classic triad of symptoms: headache, sweating, hypertension Pheochromocytoma Preoperative evaluation Urine catecholamine levels (and type of catecholamine) Plasma-free metanephrines ECG Electrolytes Preoperative treatment ALPHA BLOCK FIRST then beta block Alpha block for at least 7 days before beta block 2 weeks of therapy before elective surgery